The present invention relates to an improved air bag module comprising a housing, two opposingly mounted cylindrical inflators and a cooperating air bag. Additionally, the air bag can accommodate a tether that is formed as part of a one-piece neck or throat portion.
Reference is briefly made to FIG. 1, which illustrates a prior art passenger air bag module 20 comprising a housing 22, manifold 24, cylindrical inflator 26 and air bag 28. The air bag includes an inflatable or cushion portion 30 and a neck portion 32. The inflator 26 includes a plurality of exit ports 34 located at one end of the inflator body 36. This construction is typical of hybrid inflators. In view of the asymmetry of the location of the exit ports, inflation gas flow is asymmetric, at least in relation to a longitudinal axis of the inflator. As known, a hybrid inflator includes a pressure chamber 38 for stored gas and will usually include one mounting fastener such as a threaded bolt-like fastener 40 at a remote end of the inflator. To achieve a more uniform distribution of the inflation gas, the inflator 26 can be received within a hollow diffuser 50 (also known as a manifold) which includes a plurality of more uniformly distributed exit ports 52, which span the width of the neck 32. The diffuser 50 includes a means for attaching it and the inflator to a support structure. This means may include fasteners 54, which extend through openings 56 in the housing 22. The housing and inflator are positioned within the neck portion 32 of the air bag 28 and are enveloped by a portion of the neck, which includes facing overlapping flaps 57. The air bag is folded (not shown) and secured about the inflator and manifold. A subassembly comprising the manifold, inflator and folded air bag is inserted within the open mouth of the housing 22.
It is an object of the present invention to provide an air bag module using asymmetrical flow inflators but where the resultant gas flow into the air bag is more uniform. Another object of the invention is to provide an improved air bag in which the neck portion includes a tether. In this embodiment the neck portion and the tether are made from a single piece of material.
Accordingly the invention comprises: An air bag system comprising: a housing/inflator assembly and an air bag assembly operatively linked to the housing/inflator assembly to receive inflation gas to inflate an air bag of the air bag assembly, the housing/inflator assembly comprising: a plurality of inflators, each inflator including at least one exit port near a first end thereof, each inflator having a respective opposite second end, the housing/inflator assembly further including: first means for mounting the inflators relative to one another with at least one exit port of one of the inflators positioned adjacent the second end of a second of the inflators and with the second end of the first inflator adjacent the exit port of the second inflator. Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.